BMW Repair: Overheating, radiator hoses, hollywood california

Question
Hi Josh- 1985 318 Is- overheating problem. The car has about 140K it
drives
great, I am driving for a half hour, I look down, red lite in the temp.
area.
steam starts i pull over, let it cool and add water, drive 3-4 minutes
same
thing..this goes on for about 20 miles till I get it home.The fan blades
don't
seem wobbly, all the belts are new the hoses don't LOOK to be cracked
and
the air conditioning is brand new...could it be a thermostat problem? I
would
like to avoid bringing this into a dealer as i know  I will get reamed,
(never
lower than $500) lol. so Josh, what could it be and can I do this my
self?
also (dumb ? here) where is the themostat located and do I need to
flush the
radiator? maybe this does have to go to a repair shop. I am in
Hollywood
california


thank you in advance for your help

Answer
Charles,
 Sorry to hear about the problems, hopefully you can get this fixed in a timely fashion.

 First, you need to locate where the steam/coolant is leaking from.  If you are loosing coolant, find out where it's coming from.

 That's the first thing you need to find.  

 I know it's been hot before, but try not to let it happen again.  3/4 temp is as high as I ever let one get without pulling over.  I know it can catch you off guard, but since you know there is a problem, keep an eye on the temp and pull over if it gets to 3/4 hot.

 Also, when refilling the coolant make sure the engine is running.  Pooring cold liquid into a hot engine can cause it to crack and then you will be replacing the whole engine.

 The thermostat is on top of the engine, should be located where all the radiator hoses connecto the engine.  This could be the problem, but there are other things that could be at fault as well.

 Hope this helps,
 Josh